When all the hype is done, we will know well enough from where the London Olympics will draw their greatest supply of oxygen.
If anyone doubted this, they were surely reminded by the restatement of earth-moving brilliance made by Usain Bolt in his native Jamaica at the weekend. His 9.82sec 100 metres, the fastest in the world this year, was timely evidence of his potential to push back the barriers of athletic achievement in east London this summer.
When he did it in Beijing four years ago it was an uncanny reminder of Ben Johnson's electric surge in Seoul in 1988, when the eyes of the world switched instantly from the track to the flashing numbers on the big screen. There was also the same concern over the cleanness of what we had seen.
Bolt's glory held, Johnson's of course didn't. Four years on Bolt retains the ability to light up the world. It is the best Olympic news so far.